Clutch control mechanism



Oct. 15, 1940. v

W 5. WATTS pmwca CONTROL MECHANISM Origihal Filed Oct. 20, 1933 2Sheets-Sheet l INVENTOR #W J M0775 ATTORNEY Oct. 15, 1940,

w. s. WATTS Y r 2,217,976

CLUTCH CONTROL MECHANISM Original Filed Oct. 20, 1933 2 Sheets-Sheet 2'INVENTOR ATTORN M l/A/v 5. M4775 Patented Oct. 155 1940 PATENT OFFICECLUTCH CONTROL MECn'ANisM William S. Watts, South Bend, Ind, asslgnor toBendix Aviation Corporation, South Bend, Ind., a corporation of DelawareOriginal application October 20, 1933, Serial No.

694,437. Divided and this application December 30, 1936, Serial No.118,367

5 Claims.

This invention relates in general to power operated clutch controlmechanism for an automotive vehicle, and in particular to means forinitiating the clutch; disengaging and engaging I operations of themechanism.-.

This invention is directed to the improvement of the so-called automaticclutch of the present day, wherein the throttle operating means of thevehicle controls the valve mechanism of a manilo fold vacuum operatedmotor operably connected to the clutch. 'In this type of mechanism thepower element of the clutch motor is subjected to a varying differentialpressure to regulate'the disengagement and engagement of the clutch.

One of the wellknown commercial types of clutch motors or clutchoperators comprises a. double-ended cylinder housing a reciprocablepiston operably connected to the clutch pedal, wherein there is provideda three-way valve or B so-called dump valve constituting part of theaforementioned control valve mechanism. The control valve is preferablyoperated by the accel-' erator in such manner as to alternately connectone end of the cylinder with the intake manifold 25 of the engine and tothe atmosphere to thereby initiate the clutch disengaging and engagingoperations oi the motor.- Other valve means are provided for controllingthe efflux of air from the other end of the cylinder to vary the loading3 of the clutch plates.

invention is directed to the construction and mode of operation of thelatter valve means.

To this end there is provided a pressure differ-- ential operated bleedvalve incorporated in the 85 vent from the last-mentioned end of thecylinder, the valve and the means for operating the same being soconstructed andso interconnected with the engine of the vehicle as toreflect the R. P. M. of -the engine. This is an important 0 feature,since heretofore the bleed valve has been operated by means, such forexample as the manifold vacuum, which is subject to extraneous variablesresulting in undesirable fluctuation of the valve. The prior artrelating to controlling 45 means for the bleed valve does not suggestclutch operating mechanism including a valve structure such as disclosedby the instant invention,

wherein the mechanism provides for a loading of the clutch plates toengage the clutch in such a 60 manner that the loading'is proportionalto the engine torque. I a

Yet another object of the invention is to, pro- -vide a pressuredifferential actuated clutch operator, wherein the throttle operatingmeans of 55 the vehicle serves as a common control means for One featureof the present the throttle and the control valve mechanism of theclutch operator. To this end there is provided a valve mechanismcomprising a three-way or dump valve for initiating the clutchdisengaging and engaging operations of the clutch operator, the said"valve mechanism being controlled by the operation of the throttle. Inthe embodiment disclosed, there is also provided the bleed valvereferred to above, the same 4 comprising a power operated relay valve ofthe balanced type to provide a follow-up control of the clutch operatorin efiectingits clutch engaging operation.

Oneof the principal objects of the invention is to provide an intakemanifold operated vacuum suspended three-way valve mechanism for theclutch motor, the same being automatic in its operation with the openingand closing of the throttle. To this end there is provided a casingmember housing at one end a pressure differential operated diaphragm, avalve sleeve member being secured to said diaphragm, the sleeve beingtelescoped within the casing.

Other objects of the invention and desirable details of construction andcombinations of parts will become apparent from the followingdescription of a preferred embodiment, which description is taken inconjunction with the accompanying drawings, in which:

Figure 1 is a diagrammatic view of the preferred embodiment of theclutch control mechanism constituting the present invention;

. Figure 2 is a. sectional view of the bleed valve mechanism of Figurel;

Figure 3 is-a enlarged sectional view of the clutch motor of gum 1;

Figure 4 is an enlarged sectional view of the combined three-way valveand vacuum suspended motor for operating the same; and Figure 5 is asectional view of the check valve of Figure 1. 4

Referring now to the preferred embodiment of the invention discloseddiagrammatically in Figure 1, there is provided a clutch motor I0comprising a double-ended cylinder l2, preferably pivotally mounted to afixed portion of the vehicle, saidcylinder housing a reciprocable pistonl4 constituting the power element of the motor and operably connected toa clutch pedal I6 by linkage l8. The clutch pedal serves to operate aconventional clutch comprising driving and driven plates 20 and 22respectively. Pin and slot lost motion connections 24 and 26 provide ameans, together with the power mechanism and clutch pedal l6, wherebythe clutch may be operated either manually or by power, the connection24 providing a means whereby the clutch pedal may be depressed withoutaffecting the power means. A left compartment 28 of the cylinder I2 isalternately evacuated and vented to successively initiate adisengagement of the clutch and an engagement thereof by means of aconduit 30 connecting the clutch motor with the atmosphere and with anintake manifold 32 of an internal-combustion engine, not shown, athree-way valve 34 being incorporated in the conduit to effect theaforementioned control. The valve 34 is arranged to be operatedindirectly by an accelerator 38 through the intermediary of a throttlevalve 38 of the engine, a linkage 40. f

interconnecting these parts. The operation of the throttle varies thegaseous pressure within the manifold, which, in turn, in large measurecontrols the operation of the valve 34. Springs 42 and 44 serve toreturn the throttle valve 38 and accelerator 38 to their respective "012positions upon release of the accelerator. No claim is made to theaforementioned construction, for

the same is disclosed and claimed in the patent to Ross I. Belcia No.1,470,272, dated October 9.

-'I'he invention is, in part, directed to valve means 46 for regualtingthe eillux of air from a right compartment 48 of the cylinder I2 tothereby control the engagement of the clutch. The valve structure isdisclosed in detail in Figure 2 and includes a casing comprisinginterconnected members 50 and 52, said members housing therebetween adiaphragm member 54 secured in'position at its peripheral edge betweenthe casing members. The valve provides chambe s A and B to receiverespectively the air from the compartment 48 and the air from the intakemanifold to be described hereinafter. To the center of the diaphragm 84are secured cup-shaped washers or retainers 88 and 88. A metal spring 80is housed between a cuprshaped washer 82 and v the washer 58, the springserving to force the diaphragm 54 into engagement with a raised or landportion 84, constituting a part of the lower casing section 52.. Astonmember is adjustably mounted in the casing member 88 and abuts thecup-shaped washer 82, providing a means to mechanism not being claimedherein, inasmuch vary the compression of the spring 80. The diaphragm 84and members 88 and 88 are clamped together by a bolt 88 and a nut I0. Asindicated above, the diaphragm is normally seated, with the engineidling, upon the raised portion 84 integral with the casing member, thatportion of the diaphragm contacting the raised portion 84 constituting,together with said latter portion, a bleed or blow-oil valve, referredto in greater detafl hereinafter. A port 12 in the casing member 50 isconnected, by means of a conduit I4, with a Venturistructure I8 mountedat the air intake of a down-draft type of carburetor 18. The chamber Aof the bleed valve mechanism is connected, via a valve port 80, with thecompartment 48 of the cylinder I2 by means of a conduit 82. To a port 84in the casing member 50 is secured an inertia operated cut-oil. valve88, said as the same is disclosed and described in the application ofHarold W. Price, Serial No. 622,513,

filed July 14, 1932.

Referring now to, the operation of the abovedescribed mechanism, withrelease of the acceler-' ator the throttle is closed to idle the engine,thereby producing, by virtue of the pumping action of the enginepistons, a manifold vacuum of some twenty inches of mercury at sealevel. The valve unit 84, with the release of the accelerator, operatesto intercommunicate the manifold with the left compartment 28 of thecylinder l2. The compartment 28 is accordingly partially evacuated, theatmosphere acting upon the right side of the piston I4, and entering thecylinder via an inwardly opening' check valve 88, serving to move thepiston to the left as disclosed in Figure 3 to disengage the clutch.

An important feature of the invention relates to the control valvemechanism 34, the same comprising, in a single unit, a three-way valvemechanism operated by a motorenergized by increasing the gaseouspressure within one compartment thereof.

Describing in greater detail the aforementioned operation, when theaccelerator is released, the engine idling at the time, there results anevacuation of the clutch motor to disengage the clutch. The valveoperating motor comprises casing members 94 and 88 and a diaphragm 98secured between the valve casings. In this operation the air is drawnfrom the clutch motor I via the conduit 30, a chamber I00 in the valve,ports I02 and I04 in a plunger I08 and the valve casing member 98respectively, a by-pass conduit I08, check valve H0 and a conduit II2. S

When it is desired to engage the clutch, the accelerator is depressed,resulting in a drop in manifold vacuum to increase the gaseous pressurein the chamber C of the motor 82, the resulting differential of pressureacting on the diaphragm 98, moving the plunger I08 to the left, Figure4, to register an atmospheric port H8 in the valve casing member 98 witha port III in the plunger and cut off communication between the portsI02 and I04. The valve 24 is thus closed when the motor 92 is energizedby increasing the gaseous pressure within the compartment C thereof. Thecheck valve H0, in part, effects this result by serving to maintain thechamber to the left of the diaphragm 88 partially evacuated. Atmosphereis thusadmitted to the clutch motor, via ports H8 and I I8 and conduit80, to initiate the engagement of the clutch. After the clutch isengaged, the fluid pressure within chamber I00 increases until thespring II4 finally overcomes the fluid pressure differential acting onopposite sides of the diaphragm 88 and moves member I08 to the positionshown in Fig. 4 where the parts I02 and I04 will be in registry for asubsequent clutch-disengaging operation of motor I0 when the throttle ismoved to idling position.

With the venting of the compartment 28, the conventional clutch springs,not shown, immediately act to engage the clutch, the mode of engagementbeing determined by the mode of eillux of air from the right compartment48 of the cylinder I2. The air from the compartment passes rapidly fromthe cylinder; via a slot I20 in a connecting rod I22, effecting arelatively rapid movement of the clutch pedal to take up the clearancebetween the clutch plates. When the piston I4 and connecting rod havemoved to such a the atmosphere via the inertia operated valve 86.Thevalve spring 60 is of such strength as to be compressed by the'escaping air to open the bleed valve, said valve remaining open howeveronly until the clutch plates'have contacted with a predeterminedrelatively slight load. When this occurs the relatively high gaseouspressure within the compartment 48 of the cylinder automatically drops,to an amount however substantially above the pressure of the atmosphere,and the spring 60 automatically acts to seat the bleed valve, thisoperation beingknown in the art as a lapping of the valve. Thus,whenever the clutchis being engaged, the plates are always initiallyloaded to a predetermined amount irrespective of the worn-in conditionof the clutch facings, said loading depending upon the pro-f portioningof the parts and the strength of the clutch spring and spring 80.

The above-described operation preferably takes place with an opening ofthe throttle just suiiiciently to effect an operation of the three-wayvalve, the parts of the mechanism being adjusted to effect this result.With a continued depression of the accelerator the throttle is opened tospeed up the engine, resulting in a decrease in pressure in the chamberB acting on the diaphragm 54. This pressure, together with thesuper-atmospheric pressure acting on the lower side of the diaphragm,acts to. again crack the bleed valve, that is unseat'the diaphragm,permitting a limited amount of air to escape from the compartment A.This may be'described as a blow-off action of the valve efiecting aslight "blowing down of the clutch motor. The diaphragm 54, however,once unseated acts almost immediately thereafter to seat again, theaction being very fast, for the negative pressure developed by theventuri 16 in chamber B is insuflicient of itself to overcome the spring60 once the gaseous pressure of the air in chamber-A is reduced by theabove-described blow-off action of the bleed valve. With the escape of alimited quantity of air from the compartment 48 of thecylinder, theloading of the clutch plates is correspondingly increased by apredetermined amount in pounds.

Now, if the throttle is further operated, the above cycle of operationsis repeated, the loading of the clutch plates being increased by theaction of the clutch springs until the system is again in equilibrium,that is when the bleed valve is reseated It will be noted that the sumof the forces acting to seat the diaphragm 54 and resulting from theadditive effect of the pressure in the chamber B and the spring 60 issubstantially equal to the force exerted by the pressure within thechamber A when the system is in equilibrium and the bleed valve isseated, and the pressure in chamber Bdecreases proportionately with theincrease in pressure in chamber A. Furthermore, in order to unseat thebleed valve the pressure in chamber A must be increased so that theforce resulting from the sum of the-loading of the spring fill and thepressure in chamber B is less than the force exerted by the gas withinthe chamber A. It therefore follows. that the force exerted bythe'clutch springs at any given instant after the clutch plates havecontacted is directly proportional to the pressure in the chamber B, andtherefore directly proportional to the degree of opening of thethrottle.

The bleed or blow-oif valve is rendered operable by virtue of theevacuation of the chamber B within the valve mechanism. The velocity ofair passing through the venturi I6 is effective to operating motor,

mechanism for said motor including a ported, casing member and a. portedsleeve member teledraw the air from said chamber through the conduit Hin accordance with the degree of throttle. opening, the latterprogressively increasing the air intake via the venturi. Thus the degreeof vacuum within the chamber B is increased in direct proportion to thedegree of throttle opening. This, however, is exactly the end desired,for the loading of the clutch should be regulated in accordance with thespeed' of the engine, and the resultant torque of the -engine drivenclutch plate or flywheel to eifect the desired smooth engagement of theclutch and also obviate any possible stalling of the engine.

With the above-described mechanism there is provided in a relativelysimple fluid operated clutch operator or so-called automatic clutch theprincipal advantages of the more complicated centrifugal clutch of theday. Furthermore, it should be noted that the balanced valve mechainsmsuggested provides'the much desired follow-up to-lap type of control ofthe clutch motor. The invention heretofore described is disclosed in mycopending application Serial No. 694,437, filed October 20, 1933, whichhas eventuated in Patent No. 2,118,123 dated May 24, 1938, thisapplication constituting a division thereof.

While one illustrative embodiment has been described, it is not myintention to limit the scope of the invention to that particularembodiment,

or otherwise than by the terms of the appended claims.

I claim:

1. In a clutch control mechanism for an auto motive vehicle providedwith a throttle and an internal-combustion engine having an intakemanifold, a pressure differential operated clutch operating motor, athree-way control valve mech-' anism for said motor, means fo'roperating said' valve mechanism comprising a motor, means for causing adifferential fluid pressure on opposite sides of said motor to move thevalve mechanism to such position as to initiate clutch-engagingoperation of the clutch motor, and fluid transmitting connectionsinterconnecting said manifold, three-way valve, valve operatingmotor-and pressure differential operated motor, said. mechanism being soconstructed as to provide an operation of the valve with operation ofthe throttle to vary the gaseous pressure in the manifold.

2. In a clutch control mechanism for an auto motive vehicle providedwith a throttle and an internal-combustion engine having an intakemanifold, a pressure diiferential operated clutch a three-way controlvalve scopingly mounted within said casing, means for operating saidvalve mechanism comprising a motor, means for causing a differentialfluid pressure on opposite sides of said motor to move the valvemechanism to such a position as to initiate clutch-engaging operation ofthe clutch motor, and fluid transmitting connections interconnectingsaid manifold, three-way valve, valve ated' motor, said mechanismbeing'so constructed end of said tubular portion, a diaphragm oper- 65operating motor and, pressure diiferential op'erv ated sleeve valvemember reciprocably mounted within said tubular member. and a yieldablemember housed within said sleeve member and abutting one end of saidtubular member.

4. In a clutch control mechanism provided with a clutch-operatingpressure difierential operated motor, valve means for controlling theoperation of said motor comprising relatively movable valve members, a.motor energized, to close the valve and thereby initiate a clutchengaging operation of the motor, by increasing the gaseous pressurewithin a compartment thereof, means for operating at least one of saidvalve members comprising a motor, means for causing a differential fluidpressure on opposite sides of said motor to move said last named valvemember to such position as to initiate clutch-engaging operation of theclutch motor, said motor comprising a casing and a diaphragm memberpermanently secured to said casing, and means interconnecting saiddiaphragm member with one of said valve members.

5. Clutch control mechanism for operating the clutch of an automotivevehicle provided with a fluid motor for controlling the engagement anddisengagement of the clutch, said mechanism comprising a casing, adiaphragm within said casing, valve means for controlling said motorcomprising a valve member secured to said diaphragm, anda yieldablemember housed within said casing and valve member, said parts being soconstructed and arranged as to provide a unitary valve and an operatingmotor therefor, and means for causing a differential fluid pressure onopposite sides 01 the last named motor to move the valve member to suchposition as' to initiate clutch-engaging operation of said fluid motor.

WILLIAM S. WA'I'IS.

